Tailor-made chiral pyranopyrans based on glucose and galactose and studies on self-assembly of some crystals and low molecular weight organogel (LMOG)

Synthesis of bis[N-(p-aryl)-carbamoyloxy]alkanes as new low-molecular weight organogelators

“…Similarly, new peaks at 3.28 ppm, 1.48, and 1.27 ppm were observed for OeCH 2 in the aliphatic spacer and the methylene protons in the p-alkyl group, respectively. This type of phenomenon was also reported in other studies, 30,86 that the formation of smaller aggregates 40 leads to an increase in the non-equivalency of the protons, 30,86 but not the gelator in the solid-like gel network (as this phase is NMR silent). A similar analysis was also performed for (Table 4).…”

“…8, for gelator 5-OBu, three important observations can be made along spectra: (1) broadening of signals upon cooling, 12,19,40,81e83 (2) chemical shift variations of some signals, 84,85 (3) formation of new peaks upon cooling. 30,86 As temperature decreased to 30 C, the peak nature changed significantly due to the restricted motion of the protons in selfaggregated gel. However, the gelator NMR signals did not completely disappear in the gel state like that reported for other gelators by Terech et al, 87 showing that the gelator molecules still keep a good thermal motion in the fibers.…”

A Novel Glucose/pH Responsive Low-Molecular-Weight Organogel of Easy Recycling

“…For instance, one proton of a secondary amine at δ = 10.815 ppm at a dilute concentration of 50 mg/mL (sol) high-field shifted to δ = 10.770 ppm at a concentration of 200 mg/mL (gel), and was further high-field shifted to δ = 10.742 ppm at a concentration of 300 mg/mL (gel). The three proton-singlet of the methyl group at δ = 1.356 ppm at a dilute concentration of 50 mg/mL (sol) high-field shifted to δ = 1.273 ppm at the higher concentration of 300 mg/mL (gel). − …”

“…Since the X-ray powder diffraction pattern of the xeogels before and after the addition of glucose solution, both revealed a prominent peak at d = 3.75 Å, which represented typical π−π stacking interaction in the xerogel (Supporting Information SI-8). 36 This exhibited that the gel was directly damaged to be sol exposed to glucose solution, or to be fractured fibers which still kept aggregated layers. To support the above hypothesis, the energy profile of hydrogen-bonded complexes is calculated in Figure 7 (Gaussian 09 software package, M06/6-31G*(LANL2DZ) method, the relative energies are the free energy in the gas phase (ΔG 298 )).…”

Regulation of substituent groups on morphologies and self-assembly of organogels based on some azobenzene imide derivatives

“…Although gels are widely found in polymer systems, there has recently been an increasing interest in low-molecular-mass organic gelators (LMOGs) [7,8]. In recent years, physical gelation of organic solvents by LMOGs has become one of the hot areas in the soft matter research due to their scientific values and many potential applications in the biomedical field, including tissue engineering, controlled drug release, medical implants, and so on [9-14].…”